Messages in this thread | | | Subject | Re: [PATCH] perf_events: fix bug in hw_perf_enable() | From | Peter Zijlstra <> | Date | Mon, 01 Feb 2010 17:47:17 +0100 |
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On Mon, 2010-02-01 at 17:12 +0100, Stephane Eranian wrote: > > btw, I've also added the below, from what I can make from the docs > fixed > > counter 2 is identical to arch perf event 0x013c, as per table A-1 > and > > A-7. Both are called CPU_CLK_UNHALTED.REF, except for Core2, where > > 0x013c is called CPU_CLK_UNHALTED.BUS. > > > > If you measure 0x013c in a generic counter or in fixed counter 2 > it will count the same thing but not at the same rate. > This is true on Core2, Atom, Nehalem, Westmere. The ratio is the > clock/bus ratio.
But for Nehalem and Westmere event 0x3c umask 0x01 is referred to as CPU_CLK_UNHALTED.REF_P (Tables A-2 and A-4),
Fixed Counter 2 is referred to as CPU_CLK_UNHALTED.REF (Table A-7).
For Core2 and Atom (Table A-8, A-9) it is called CPU_CLK_UNHALTED.BUS, for these entries there is talk about a fixed ratio.
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